My opinion? Low. Very low. It doesn't measure how long the blades/curtains are actually open, it just displays the sounds the shutter makes and you guess what sound represents opening, and what sound represents closing.
I use a phototransistor and a dual trace scope, this actually tells me how long light is coming through the shutter.
The tester does not measure or record the sound of the shutter. It records the amount of time that the shutter is open.
When the shutter opens the light beam strikes a photoresistor. The circuit creates a signal that is recorded in time.
When the shutter closes and breaks the light beam the circuit creates a second signal that is recorded in time.
The time between signals is measured, that is the shutter speed as measured.
The tester does not measure or record the sound of the shutter. It records the amount of time that the shutter is open.
When the shutter opens the light beam strikes a photoresistor. The circuit creates a signal that is recorded in time.
When the shutter closes and breaks the light beam the circuit creates a second signal that is recorded in time.
The time between signals is measured, that is the shutter speed as measured.
Mr von Hoeugh I would be interested in your technique. I have a Tek 2335 scope, which would more than fit the job. My opinion of the tester mentioned wasn't much either. What did you do''fabricate a plate to put on the film rails with 2 phtotransistors, one at the left of the film gate and 1 on the right? What is your opinion of the mentioned tester on an iris shutter?
It occurred to me some time after the above post that you would probably need a later model scope capable of re-playing a trace.
The phototransistor is biased so it's just below the threshold of conducting, and it's masked so there's about a .025" slit (parallel to the curtain edges) for light to get to it. I place the gizmo just behind the shutter and trip the shutter. This gives a somewhat square wave on the scope, it's easy to read due to the persistence of the phosphors. Just calibrate the timebase for whatever speed(s) you're measuring, I use WWV as a standard. On a 35mm shutter, you can move the cell from left to right to measure the slit uniformity.
I wouldn't waste my time with that shutter tester on anything more sophisticated than a Packard.
Well that counts me out. I got rid of both my Hammarlund HQ180's. All I have is my Hammarlund HQ110, ham band only. So no WWV for me. This house is just too small for all my gadgets.
From the ad, no mention of anything to do with light:
"No battery and no maintenance needed! The tester works just like an electret microphone (a microphone that does not need a power supply). I have not heard of any PC sound cards that don't support electret microphones but you should still check if your sound card does"
I don't get it. I comment that I have the same product and confirm that it's measuring light, not sound, and it just gets glossed over? LOL.
I rather well thought it used light. I've done some study on FP shutter testers, and it seems the best design has 2 cells--1 on left and 1 on right.
I don't get it. I comment that I have the same product and confirm that it's measuring light, not sound, and it just gets glossed over? LOL.
Who knows. At any rate I spent a rainy Saturday making a trip to radio shack and putting one together from a circuit diagram I found on line. Great fun and proved accurate using my Nikon F100 and several of my Nikon primes as a base line.
Who knows. At any rate I spent a rainy Saturday making a trip to radio shack and putting one together from a circuit diagram I found on line. Great fun and proved accurate using my Nikon F100 and several of my Nikon primes as a base line.
Who knows. At any rate I spent a rainy Saturday making a trip to radio shack and putting one together from a circuit diagram I found on line. Great fun and proved accurate using my Nikon F100 and several of my Nikon primes as a base line.
I have one of the cable testers shown, I made a small box for my Technika lensboards to sit in with the receiver at one end and an LED Maglite at the other, I tested all of my LF lenses and discovered that all my newer Copal shutters were accurate and repeatable up to 1/60, then there was a 1/3rd stop overexposure at 1/125 and at 1/250 and 1 stop at 1/400, in fact the graphs for1/250th and 1/400th were almost the same.Shutter testers are devices for increasing photographers sense of insecurity, because if they are inaccurate what are you going to do about it ?, if I suspect they are out I get mine tested by a professional and have him adjust them if neccesary.
guys - remember one thing.
Any simple shutter tested will only measure the elapsed time of a shutter, which is fine for leaf shutters, or to check the exposure a focal plane shutter is giving at the point where the tester cell is fitted in the camera plane.
It won't tell you 1st and 2nd curtain speeds, or whether a shutter is capping - for that you need a far more advanced shutter tester...
However if all you want is a time, then these testers seem to work well, based on the couple I've played with over the years..
cheers
Andrew (former Camera Technician with Canon Australia)
True, and the guy that makes those Ebay ones talks about that in the MFlenses thread linked above.
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